Field of Invention
The present invention belongs to the field of thermoelectric materials, which relates to the preparation of CrN material and discusses its potential value in thermoelectric applications.
Description of Related Arts
Thermoelectric material is a kind of functional material which can convert thermal energy and electric energy from each other. Based on the seebeck effect and peltier effect, it can be used for thermoelectric power generation and static cooling, and has no pollution, no mechanical rotation, no noise and flexible installation. At present, thermoelectric materials have shown a trend of vigorous development in military, aerospace, industrial waste heat utilization, automobile exhaust waste heat utilization and other fields, and have great commercial potential.
The conversion efficiency of thermoelectric materials is evaluated by dimensionless figure of merit ZT (ZT=S2σT/κ), where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature, and κ is the thermal conductivity. The higher the ZT value, the higher conversion efficiency of thermoelectric materials. The recent emergence of high-ZT materials is encouraging. However, the material that can be applied on a large scale is scarce. Considering the working conditions of thermoelectric devices, the large temperature difference between the hot and cold side may lead to deformation and collapse of the device, which can greatly influence the efficiency and service life. Even the current commercial thermoelectric materials such as Bi2Te3 and PbTe includes these challenging aspects as well. In order to address these issues, materials with better mechanical properties and high thermal stability are needed.
CrN is usually prepared by reaction of metal chromium or chromium halide with ammonia in industry. The reaction usually takes a very long time (2 or 3 weeks), which is greatly reduces the production efficiency and economic benefit of the CrN industry. Other methods to preparation CrN such as mechanical alloying method, benzene hot method, high-energy ball mill method due to the long production cycle, the low purity and the harsh reaction conditions which are not suitable for mass production. Therefore, it is important to explore a quick and efficient method for the preparation of CrN.